• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.3
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• pp.21-28
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• 2003

It is essential to use base papers having proper surface characteristics in coating operation for improving coated paper quality and coater runnability. To fulfill these purposes surface sizing of coating base stock with anionic oxidized starch is commonly practiced. It is suggested that use of cationic starch for surface sizing rather than conventional oxidized starch will improve coated paper quality since cationic starch penetrates less into paper structure because of its strong electrostatic interaction with anionically charged paper surface. Strong interaction of cationic surface sizing starch with anionic coating color is expected to promote rapid immobilization of the coating color and improve coating holdout and optical property. The immediate objective of this study was to examine the influence of surface sizing starches on the properties of coated papers. Structural characteristics of the coatings formed on the substrate surface sized with cationic and anionic starches were examined. To enhance the efficiency of cationic surface sizing starch on coated paper properties, strongly charged cationic polymers were added to the surface sizing starch and its effect on coated paper properties was evaluated. Results showed that opacity and light scattering coefficient of coated paper were higher when base paper surface sized with cationic starch was used. Addition of less than 1% of cationic poly-DADMAC to the cationic surface sizing starch improved the opacity of coated paper significantly.

• Composites Research
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• v.32 no.6
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• pp.375-381
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• 2019

Multiwalled carbon nanotubes (MWCNTs) are covalently functionalized with isocyanates by directly reacting commercial hydroxyl functionalized MWCNTs with excess 4,4'-methylenebis (phenyl isocyanate) (MDI) and hexamethylene diiosocyanate (HDI). HDI-modified MWCNTs results in a higher surface isocyanate density than MDI-modified MWCNTs. Anionic ring-opening polymerization of ε-caprolactam is conducted using a sodium caprolactam initiator in combination with a di-functional hexamethylene-1,6-dicarbamoylcaprolactam activator in the presence of isocyanate functionalized MWCNTs. This polymerization proceeds in a highly efficient manner at relatively low reaction temperature (150℃) and short reaction times (10 min). During the polymerization, the isocyanate functionalized MWCNTs act not only as reinforcing fillers but also as second activators. Nanocomposites with HDI modified MWCNTs exhibit higher reinforcement and faster isothermal crystallization than MDI modified MWCNTs. The results show that PA6 chains grow more effectively from HDI modified MWCNT surface than from MDI modified MWCNT surface, resulting in stronger interaction between PA6 and MWCNTs.

• Macromolecular Research
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• v.13 no.5
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• pp.367-372
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• 2005

As a preliminary work for the preparation of nylon 6/c1ay nanocomposites by reactive extrusion, nylon 6/c1ay nanocomposites were prepared by anionic polymerization in a flask. In order to investigate the effect of the intercalation of clay layers, the clay feeding times, such as in pre-mixing where the clay was fed before initiation of polymerization and in after-mixing method where the clay was fed after initiation of polymerization, were changed. The appearance of the WAXD peak of nanocomposites prepared by the pre-mixing method was obvious and the tensile strength was decreased compared with that of pure nylon 6, which indicates that the clay layers were not dispersed and distributed. During the preparation of the nanocomposites by the after-mixing method, disordering of the clay layers was observed with increasing clay addition time and was suspected to result from the rapid polymerization of nylon 6 within the clay layers.

• Journal of Microbiology and Biotechnology
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• v.29 no.9
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• pp.1361-1368
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• 2019

Codium fragile is an edible seaweed in Asian countries that has been used as a thrombolytic, anticoagulant, antioxidant, anti-inflammatory, and immune-stimulatory agent. Ginseng has also been known to maintain immune homeostasis and to regulate the immune system via enhancing resistance to diseases and microorganisms. In this study, anionic macromolecules extracted from C. fragile (CFAM) were orally administered with red ginseng extract (100 mg/kg body weight) to cyclophosphamide-induced immunosuppressed male BALB/c mice to investigate the immune-enhancing cooperative effect of Codium fragile and red ginseng. Our results showed that supplementing CFAM with red ginseng extract significantly increased spleen index, T- and B-cell proliferation, NK cell activity, and splenic lymphocyte immune-associated gene expression compared to those with red ginseng alone, even though a high concentration of CFAM with red ginseng decreased immune biomarkers. These results suggest that CFAM can be used as a co-stimulant to enhance health and immunity in immunosuppressed conditions.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.320-323
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• 2003

The effects of pH on the binding of human granulocyte-macrophage colony-stimulating factor (hGM-CSF) expressed from transgenic plant cell suspensions to cationic and anionic exchange resins were investigated. In terms of stability, the optimum pH was found to be 5-7. In the case of using buffer exchange, when CM-sepharose was used as a cationic exchange resin, the best binding pH was 4.8 (77%) and when DEAE-sepharose was used as an anionic exchange resin, the best binding pH was 5.5 (74%). Without using buffer exchange, the optimum pH was 4.6 and the adsorption yield was 84%. From these results, a possibility of overcoming the degradation and instability of secreted protein product by in firm adsorption was found.

• Journal of Environmental Science International
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• v.19 no.2
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• pp.247-254
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• 2010

Ultrasound and Surfactant aided soil washing process has been shown to be an effective method to remove diesel from soils. The use of surfactants can improve the mobility of diesel in soil-water systems by increasing solubility of adsorbed diesel into surfactant micelles. However, a large amount of surfactant is required for treatment. In addition, synthetic surfactants, specially anionic, are more toxic and the surfactant wastewater is hard to treat by conventional wastewater treatments even by AOPs. Ultrasound improves desorption of the diesel adsorbed on to soil. The mechanisms are based on physical breakage of bonds by hot spot, directly impact onto soil particle surface, the fragmentation of long-chain hydrocarbons by micro-jet and microstreaming in the soil pores. The use of ultrasound as an enhancement method in both anionic and nonionic surfactant aided soil-washing processes were studied. And all experiments were examined proceeded under CMC surfactant concentration, frequency 35 khz, power 400 W, Soil-water ratio 1:3(wt%), particle size 0.24 ~ 2mm and initial diesel concentration. 20,000 mg/kg. Combination with ultrasound showed significant enhancements on all the processes. Especially, nonionic surfactant Triton-X100 with ultrasound showed remarkable enhancements and diesel removal rate enhanced by ultrasound helps desorpting of surfactant adsorbed onto soils which prevented decreasing surfactant activity.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.299-304
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• 2005

There have been many efforts to use anionic hydrogels as oral protein delivery carriers due to their pH-responsive swelling behavior. The dynamic swelling behavior of poly(methacrylic acid-co-methacryloxyethyl glucoside) [P(MAA-co-MEG)] hydrogels was investigated to determine the mechanism of water transport through these anionic hydrogels. The exponential relation $M_t/M_{\infty}=kt^n$ was used to calculate the exponent, n, describing the Fickian or non-Fickian behavior of swelling polymer networks. The mechanism of water transport through these gels was significantly affected by the pH of the swelling medium. The mechanism of water transport became more relaxation-controlled in the swelling medium of pH 7.0 that was higher than the $pK_a$ of the gels. Experimental results of time-dependent swelling behavior of the gels were analyzed with several mathematical models. Using ATR-FTIR spectroscopy, the effect of ionization of the carboxylic acid groups in the polymer networks on the water transport mechanism was investigated.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.11
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• pp.735-742
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• 2012

This study tried to find a suitable method for enhancing the foam stability of cationic surfactants that normally generate less foam or no foam. Several trials were made to enhance the foam stability: addition of anionic surfactant, colloids and polymer. Cationic starch (CA-ST) did not form foam at all, while the foam stability of two other cationic surfactant also showed low levels; methyl triethanol ammonium methyl sulfate distearyl ester (CEQ90) for 46 sec. and Cetyl trimethyl ammonium chloride (CM29) for 31 seconds. Foam stability of cationic surfactants were significantly affected by addition of anionic surfactant, sodium dodecyl sulfate (SDS). Foam stability of CA-ST was significantly enhanced by addition of SDS, while those of CEQ90 and CM29 were decreased. Addition of colloids ($SiO_2$, kaolin) and polyvinyl alcohol (PVA) enhanced foam stabilities of CEQ90 and CM29. However, CA-ST did not form foam even in the presence of colloids or PVA. Effect of simultaneous addition of colloids and anionic surfactant on foam stability of cationic surfactant showed that foam stability of cationic surfactant was more influenced by addition of anionic surfactant than colloids. Effect of simultaneous addition of PVA and anionic surfactant on the foam stability of cationic surfactant also showed that presence of anionic surfactant significantly affect the foam stability of cationic surfactant. Foam stability of CA-ST was greatly increased to 8,780 seconds by addition of SDS 0.14% and PVA 2.5%. The foam stability of CA-ST was 8 times higher than CEQ 90. This study suggested that cationic surfactants not forming foam can generate foam by addition of anionic surfactant and its stability can be additionally increased by addition of colloids and PVA. The study results showed that enhancement in foam stability of cationic surfactant was prominently affected by the concentration of anionic surfactant added.

• Membrane and Water Treatment
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• v.9 no.5
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• pp.335-342
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• 2018

Micelle-Enhanced Ultrafiltration (MEUF) is a membrane separation processes that improving ultrafiltration process with the formation of micelles of the surface active agents. Surface active agents are widely used to improve membrane processes due to the ability to trap organic compounds and metals in the treatment of industrial waste water. In this study, surface active agents are used to improve micelle-enhanced ultrafiltration (MEUF) to reduce chemical oxygen demand (COD), total dissolved solid (TDS), turbidity and clogging the membrane in dairy wastewater treatment. Three important operational factors (anionic surface active agent concentration, pressure and pH) and these interactions were investigated by using response surface methodology (RSM) and Box-Behnken design. Results show that due to the concentration polarization layer and increase the number of Micelles; the anionic surface active agent concentration has a negative effect on the flux and has a positive effect on the elimination of contamination indices. pH, and the pressure have the greatest effect on flux. On the other hand, it could be stated that these percentages of separation are in the percentages range of Nano-filtration (NF). While MEUF process has higher flux than NF process. The results have been achieved at lower pressure while NF process needs high pressure, thus making MEUF is the replacement for the NF process.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.712-715
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• 2009

본 연구에서는 고밀도, 고촉진 가스하이드레이트 생성 촉진제 (promoter)의 개발을 위하여 음이온성 멀티체인형 게면활성제를 제조하였다. 또한 각 계면활성제의 알킬그룹의 길이에 따라 같은 조건에서의 계면활성제의 촉진 효과를 비교하였다. $1^{\circ}C$에서 35bar,40bar로 압력을 달리하여 비교 실험하여 메탄 하이드레이트 생성속도를 측정하고, 각 조건에서의 계면활성제의 촉진 효과를 비교하였다. 알킬그룹의 길이가 짧을수록, 압력이 높을수록 촉진 속도가 빠르다. 또한 기존의 상용화된 SDS(Sodium dodecyl sulfate)보다 본 연구에서 제조한 C10의 음이온성 멀티체인형 계면활성제가 SDS 대비하여 소량으로도 충분한 효과를 나타냄을 확인하였다.